Ibn al-Salah said in his
Muqaddimah: "We know not its like in its field." In other words, it is the best of the Sunan works.
Al-Nawawi said in al-Taqrib that one should be devoted to it, as nothing has been written like it, and
Al-Suyuti, commenting on this statement in Tadrib al-Rawi, agreed.
Al-Sakhawi said in Fath al-Mughith that one must not limit oneself from it (by sufficing with the other sunan works of Abu Dawud, al-Nasa’i, and al-Tirmidhi) due to its comprehensiveness in most of the ahadith al-ahkam.
Al-Sakhawi further added that its true rank is only after the Sahihayn of al-Bukhari and Muslim, coming before the sunan of Abu Dawud, al-Nasa'i, and al-Tirmidhi, which take precedence only by merit of being earlier and thus with shorter chains.
Al-Dhahabi said there is nothing like it and considered it to be one of the four masterpieces a scholar cannot do without, alongside al-Muhalla by Ibn Hazm, al-Mughni by Ibn Qudamah, and al-Tamhid by Ibn Abd al-Barr. ==Commentaries==